Numerous commercially-available automatic swimming pool cleaners exist. Although some utilize electricity to power internal pumps and motors, many connect instead (indirectly) to pumps located externally of the pools. Using flow of water to or from the pumps, the automatic pool cleaners themselves traverse the bottoms (and sometimes walls and other surfaces) of pools, vacuuming debris resting thereon.
Automatic pool cleaners connected, indirectly, to the inlet of pumps are often called "suction-side" cleaners, as the suction created by the pumps draws, or evacuates, water through the cleaners. One example of a suction-side cleaner is illustrated in U.S. Pat. No. 5,014,382, which patent is incorporated herein in its entirety by this reference. The cleaner includes a valve (which may but need not necessarily be a diaphragm), which in use periodically interrupts the flow of water through the cleaner body. The interruption in flow assists in moving the cleaner about the bottom (and other surfaces) of a swimming pool.
By contrast, automatic pool cleaners connected (again indirectly) to outlets of pumps are termed "pressure-side" cleaners. U.S. Pat. No. 4,835,809 to Roumagnac, also incorporated herein in its entirety by this reference, discloses an example of such a pressure-side cleaner. According to the Roumagnac patent, the cleaner connects to the "recycle mouth," or return line, of the pool filtration system. Flow of pressurized water through the cleaner creates a low-pressure region within its body, permitting aspiration of debris-laden water from the pool into the body.
Although capable of removing detritus from pools, automatic swimming pool cleaners historically have been unable to assist in purifying water chemically. Instead, such purification has sometimes occurred using devices wholly separate from the automatic cleaners. These devices frequently include pressure vessels and are located externally of the pools themselves.
U.S. Pat. No. 4,504,387 to LeMire, et al. discloses exemplary equipment for purifying bodies of water, including swimming pools, spas, and hot tubs, utilized recreationally by human beings. As shown in FIG. 1 of the LeMire, et al. patent, swimming pools conventionally include pumps, filters, and recycling systems; while a pump is operating, water is continually withdrawn from a pool, passed through a filter, and returned to the pool via the recycling system. By positioning water purification equipment between the outlet of the pump and the return mouth of the pool, pressurized water exiting the pump can be purified prior to its return to the pool.
Water purification equipment of the type detailed in the LeMire patent is, as suggested above, designed for placement outside the boundaries of the pool. Consequently, it includes a stand or base on which an outer casing is positioned. The stand maintains the casing in an upright stance, whether located above soil, concrete, or asphalt.
The casing, moreover, contains an inlet and an outlet, both of which are plumbed into the recycling system of the pool. As a result, the water purification equipment is closed to the ambient environment and receives only water passed from the outlet of the pump. By this reference applicants incorporate herein the entirety of the LeMire, et al. patent, as well as the entireties of U.S. Pat. Nos. 5,352,369 to Heinig, Jr., 5,660,802 to Archer, et al., and 5,772,896 to Denkewicz, Jr., et al., which disclose other equipment and techniques for purifying water.
U.S. Pat. No. 5,269,913 to Atkins, additionally incorporated herein in its entirety by this reference, describes a mechanical debris trap for use in connection with suction-side automatic swimming pool cleaners. As recited in the Atkins patent, the trap has an internal strainer, or filter, and
a "T" configuration, with the inlet/outlet tube making up the top of the "T" and a housing containing the filter and a relief valve, drain, or similar device making up the base of the "T." The inlet/outlet tube is intersected at midpoint by a tube or downspout perpendicular to the inlet/outlet tube that prevents direct flow through the inlet/outlet tube but is open on the inlet side. The perpendicular tube penetrates the filter and terminates in an open end within the filter.
See Atkins, col. 2, lines 10-18. The trap is spliced into a flexible hose leading to an automatic pool cleaner; in use, "[w]ater and debris entering the inlet are directed downward into the interior of the filter by the perpendicular tube," id., lines 32-34, with debris being trapped within the filter and water migrating through the filter to the outlet of the trap.
The debris trap of the Atkins patent additionally (optionally) includes a relief valve in the bottom of the housing. As described therein, the valve "allows water to be drawn into the housing to balance the fluid flow to or from the cleaner head." Id., lines 40-42. Such drawing occurs when the pool cleaner or a system regulator valve becomes plugged or blocked and is intended to equalize the pressure within the overall filtration system. See id., col. 4, lines 8-14. The primary water flow through the trap, therefore, remains via the inlet/outlet tube.
Neither the LeMire nor the Atkins patent details equipment adapted to purify water chemically while the water is within a swimming pool. Likewise, neither patent addresses use of any equipment designed to cooperate with both pressure- and suction-side automatic swimming pool cleaners. Accordingly, for at least these reasons an in-line, in-pool system for chemically treating water in conjunction with an automatic swimming pool cleaner (whether suction- or pressure-side) would be useful.